This invention relates to fuel injection pump timing devices and, more specifically, to such a mechanism including improved means for setting the timing.
Prior art of possible relevance includes the following U.S. Pat. Nos.: Backlund et al. 2,977,778, issued Apr. 4, 1961; Kranc et al. 3,258,937, issued July 5, 1966; and Barton et al. 3,601,109, issued Aug. 24, 1971.
As is well known, in fuel injected, internal combustion engines, the point at which fuel is injected into each cylinder during the operating cycle plays a large part in determining engine output and efficiency. In variable speed engines, means are provided whereby the point in the operating cycle at which injection occurs is advanced as engine speed increased for this purpose. The foregoing prior art patents are representative of mechanisms which accomplish this function.
However, the use of such mechanisms does not ensure optimal timing. For example, if the timing is initially improperly set, even though such mechanisms will perform their intended function of advancing the timing with engine speed, there will remain improper adjustment at all speeds, resulting in inefficiency and lower outputs.
In the case of many prior art mechanisms, achieving proper initial timing is difficult since access to components is extremely limited. Moreover, in many such devices, it is virtually impossible to make adjustments while the engine is running so as to compensate for timing requirements that may vary slightly from one engine to the next even though the engines are ostensibly identical. It is also difficult to adjust timing in many prior art constructions to accommodate variations in timing requirements imposed by differing operating environments.